I've also been on Shaw since pretty much continuously since the first month they offered service, and I live in one of the first cities activated. Yes, about 14 years. Haven't used their email or web services since the first year.
I had one incident with Shaw which was very annoying. An OpenBSD firewall just suddenly stopped working with no change on my part. If just the firewall accessed the internet, it worked normally. But as soon a NAT client relayed traffic through the firewall concurrently, responses from the Shaw head-end would cease to arrive, for about 30 seconds. If I had ping running, I'd seen 30 ping packets go out, then all of sudden 30 pink packet responses, then maybe a few other packets, then another 30 second hiatus. Who knows, maybe I had something unorthodox in my pf configuration about handling all the background arp chatter. I had only ever aspired to "works for me" with my pf configuration.
The Shaw technician determined that the problem was customer premise equipment by showing that routing my service into a Mac with no firewall present worked just fine. The network trace showing their head-end buffering 30 seconds worth of ping responses and then blurping them back in a packet noogie didn't strike him as a hinting toward an anomaly with their own administration.
This had happened once before for a week or so, and then suddenly cleared itself up with no intervention on my part. The next time it was permanent.
I didn't feel like fighting with them or with messing with my firewall configuration, so I ordered Telus as a backup, and that worked perfectly with my firewall without changing anything. While I had both services, I observed that Shaw is fundamentally superior. You don't see this in data rates (not often) but you do see this whenever you're surfing the web with a big download running in background. Telus gets very chunky. I was banned by a family member from downloading anything on our Telus connection during a remote session to the office. Shaw has tiny lurches, too, but you almost don't notice them. This whole problem, likely having something to do with buffer bloat, has become progressively worse (not better) over the last 14 years, with the biggest uptick in chunkiness right around the time Netflix became popular.
Telus is also a vastly more irritating company to deal with. Don't even get me started, I could go for a week.
Shaw is no angel, but over the term of my experience, they've about as enlightened and as reliable as any ISP on the planet. There's no such thing as an ISP that never pisses anyone off.
However, by some miracle of economics, I'm now paying more for essentially the same service than I was 14 years ago. I was a heavy user then. Good grief, I downloaded 100 megabyte service patches over dial-up the year before Shaw offered broadband. Now that 100MB patch is 700MB ISO, so there has been usage inflation, yet hardly outstripping technological progress. Somehow in the telecoms industry, economies of scale run contrary to every other field of economic endeavor.
The Shaw email outage is a brutal error, but I wouldn't trade Shaw for 90% of the other ISPs out there, not without a gun to my head. This is easier for me to say having the wits to set myself apart from ISP email services 13 years ago. This also made it easier to switch pipes when I did experience my Shaw difficulties.
Note that my PF problems went away when I rebuilt my ruleset from scratch on a FreeBSD server that replaced my old OpenBSD firewall, when time permitted me to mess with this.
I'm sure it was a case where something unusual in my configuration triggered a bug in how the service was configured on their side. Shaw is not the kind of ISP that digs into anomalies even if you shove the packet trace right in their face. Maybe after this email thing boils over, they'll get religion on pursuing those small anomalies people were noticing a week before one final fault routed all their received email into the giant bit bucket.